The Oklahoma man suspected of beheading a former co-worker at a food distribution warehouse last week, who was shot by another employee trying to thwart the attack, was placed under arrest in a hospital where he underwent surgery, authorities said on Saturday.

Alton Nolen was charged with first degree murder and assault with a deadly weapon when he emerged from sedation, said Moore, Oklahoma, police sergeant Jeremy Lewis.

Nolen is suspected of killing Colleen Hufford, 54, and stabbing Traci Johnson, 43, who apparently were attacked randomly at the Vaughan Foods facility in Moore on Thursday, Lewis said.

Nolen, 30, had been fired from the plant moments earlier.

He was shot by Vaughan’s chief operating officer during the attack, said Lewis.

Nolen underwent surgery at a local hospital and was expected to survive, he said.

Authorities waited until he was coherent and could understand the charges before placing him under arrest on Friday afternoon, Lewis said.

Johnson was in stable condition in intensive care, he said.

Nolen had reportedly tried to convert his colleagues to Islam, and the FBI was looking into his background, police said on Friday.

Islamist militants fighting in Iraq and Syria have released videos that purported to show the beheadings of two Americans and a British aid worker.

After being fired, Nolen went to Vaughan’s main office, where he stabbed Hufford several times and then severed her head, Lewis said.